A252071 Number of (n+2) X (4+2) 0..2 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 or 4.

375, 1135, 5085, 21862, 92225, 391934, 1669294, 7114867, 30309042, 129016031, 549319037, 2339547000, 9963141845, 42425232250, 180661430026, 769335984173, 3276146397838, 13951092432179, 59409215103993, 252988054381898, 1077323450291751, 4587668696634158, 19536105244857606

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 2*a(n-1) +5*a(n-2) +14*a(n-3) +34*a(n-4) -16*a(n-5) -79*a(n-6) -150*a(n-7) -94*a(n-8) +581*a(n-9) +457*a(n-10) -913*a(n-11) -631*a(n-12) +692*a(n-13) +433*a(n-14) -236*a(n-15) -116*a(n-16) +72*a(n-17) -57*a(n-18) -32*a(n-19) +38*a(n-20) -15*a(n-21) +5*a(n-22) +11*a(n-23) -4*a(n-24) for n>26.

Example

Some solutions for n=4:
..2..1..2..2..1..2....2..2..2..2..1..2....1..2..2..2..2..1....2..2..2..2..2..2
..1..2..2..2..2..1....2..2..2..2..2..2....2..2..2..2..2..2....2..2..2..1..2..2
..2..2..2..2..2..2....2..1..2..2..2..2....2..2..2..2..2..2....2..1..2..2..2..2
..2..1..2..2..2..2....2..2..2..1..2..2....1..2..2..2..2..2....2..2..2..2..2..2
..2..2..2..2..2..1....2..2..2..2..2..2....2..2..2..2..2..1....1..2..2..2..2..2
..2..2..2..2..2..2....1..2..2..2..1..2....2..2..2..1..2..2....2..2..2..2..2..1

Crossrefs

Column 4 of A252075.

Sequence in context: A369663 A249550 A045200 * A388058 A247263 A251652

Adjacent sequences: A252068 A252069 A252070 * A252072 A252073 A252074

Keyword

nonn

Author

R. H. Hardin, Dec 13 2014

Status

approved